The present invention relates generally to communication networks, and more particularly to a private or corporate wireless network having a virtual HLR (home location registry) and a method of operating the same.
Home location registries or HLRs are used in communication systems to record and store information relating to users or subscribers of the systems. Prior art public communication systems typically include a small number of HLRs, for example, in the United States there are just two to three public HLRs per state per operator. A prior art communication system 10 with a small number of HLRs 12 is shown in FIG. 1. Referring to FIG. 1, each of the HLRs 12 are connected to a network of communication nodes or subsystems through a gateway mobile switching center (GMSC 16). Each communication subsystems in the communication network typically includes: (i) a GMSC 16 or a mobile switching center (MSC 18) to communicate with a public switched telephone network (PSTN 19) and other MSCs or GMSCs in the communication system 10, (ii) one or more base station controllers (BSCs 20) to control and communicate with one or more base transceiver stations (BTS 22), and (iii) a number of BTSs to communicate with mobile stations (MS 24). The HLRs 12 are further connected to an SS7 signaling network 26 through a mobile access part (MAP) interface or link to enable communication to other GMCs or visitor location registries (VLRs). Although not shown, transfer of signaling information between the MSCs 18 and GMSCs 16, as opposed bearer information, is also communicated through the SS7 signaling network 26. Each HLR 12 is identified to the SS7 network by a unique node number of address, for example, an ITU E-series address such as an E. 164 (PSTN telephone numbers) or E.212. The HLRs 12 are further connected through a maintenance interface, such as an E1 or T1 trunk, to an operation support system (OSS 28), which includes an operation management controller (OMC 30). The OMC 30 serves to configure and manage each of the HLRs 12. For example, the OMC 30 is used to add, delete or alter the profile of subscribers to the communication system 10; to configure the system by specifying to which HLR 12 to direct requests for information on a particular subscriber, and alert operators to failure or degraded performance of an HLR.
The above prior art communication system 10 suffers from a number of problems or disadvantages, including: vulnerability where failure of a single HLR 12 or more can take down the system; delay and congestion of the maintenance interface due to the necessity of backhauling information or access requests to the HLR even when connecting a communication path between two MSs 24 using the same MSC 18 resulting in inefficient utilization of system resources-and the expense of purchasing and operating large servers or switches on which the HLRs reside.
Another approach, which alleviates some of the above problems and is commonly used by operators of private or corporate communication systems, is shown in FIG. 2. Referring to FIG. 2, is this approach the communication system 10 has a large number of HLRs 12, each at a different site 32 and each associated with one or a small number of GMSCs or MSCs. Each HLR 12 has its own OMC 30, which are coupled to a telecommunications management network (TMN 34) through which operators can operate the OMC to configure and manage the associated HLR. It will be appreciated that this approach increases reliability by eliminating the possibility of the failure of a single HLR taking. a large portion of the communication system. Efficiency of the system is also increased by reducing or eliminating the need to backhaul information or access requests to one or a few large HLRs distant from the point of origination for the call.
Although in many ways an improvement over communication systems having a single or few large HLRs, the above approach is still not entirely satisfactory. One problem with the above approach is increases the time and expense incurred in configuring and managing the multiple HLRs. For example, adding, deleting or altering the profile of a user can require the operator to access all or a substantially of the HLRs. Moreover, adding HLRs can require reconfiguration of the communication system and all HLRs therein by highly skilled programmers, a time consuming an expensive task. Finally, it may not be possible to add HLRs in some countries or regions, since the number of unique node numbers by which each HLR is identified is limited and usually tightly regulated by a governmental authority.
Accordingly, there is a need for a communication system and method of operating the same that provides increased robustness and reliability. There is a further need for an system and method that consolidates control and management of operation functions, subscription functions and alarm functions for the multiple HLRs. There is a still further need for a system and method that improves utilization of system resources through the reduction or elimination of backhauling of messages from an originating MSC to a remote HLR.
The system and method of the present invention provides these and other advantages over the prior art.
It is an object of the present invention to provide a communication system or network having a logical or virtual home location registry (HLR) and a method for operating the same.
In one aspect, the present invention is directed to a private or corporate network having a number of corporate wireless networks located at a number of sites, each of the corporate wireless networks having a physical HLR, an internet protocol (IP) network coupling each of the corporate wireless networks to one another, an operation management controller (OMC) coupled to a public mobile switching center (MSC), and an HLR management routing function or routing function coupled to the OMC and to the corporate wireless networks via the IP network. Generally, the routing function is configured to route access requests from the OMC to the physical HLRs, and the OMC is configured to manage the physical HLRs to provide a single virtual HLR for the corporate wireless networks.
In one embodiment, the OMC is an OMC of a single corporate enterprise, and the sites include separate branches of the enterprise. Alternatively, the corporate network includes an additional OMC of another private enterprise, and the sites include branches of both enterprises at separate sites, and branches of both enterprises at a shared site. Preferably, the corporate wireless network at the shared site includes an HLR containing information relating to branches of both enterprises at the shared site, and each of the OMCs are configured to manage each of the physical HLRs at their associated separate sites and the shared site to form a virtual HLR for the associated enterprise.
In another aspect, the present invention is directed to a communication network having a public and private or corporate network. Generally, the public network includes a public wireless network with a public mobile switching center (MSC). The corporate network includes a number of corporate wireless networks located at a number of sites, each of the corporate wireless networks coupled to the public MSC, several or all of the corporate wireless networks having a physical HLR. In accordance with the present invention, the corporate network further includes an OMC coupled to the public MSC, and an IP network, such as a private intranet, coupling each of the corporate wireless networks to one another. An HLR routing functions couples to the OMC and to the corporate wireless network via the IP network, and is configured to manage each of the physical HLRs to provide a single virtual HLR for the corporate network. Preferably, the corporate wireless networks communicate with one another using a proprietary signaling scheme including information identifying each physical HLR. More preferably,: the physical HLRs are identified by IP addresses, the HLR routing function includes a central address table (CAT) coupled to each of the number of corporate wireless networks and to the OMC via the IP network. Alternatively, the HLR routing function can include a domain name server, which identifies the particular physical HLR in which each named record is stored.
In another embodiment, the public network further includes a public switched telephone network (PSTN), and the corporate network further includes private branch exchanges (PBXs) at several or all of the sites linked to the PSTN and to the corporate wireless network at the site.
In yet another aspect, the present invention is directed to a method of operating a corporate network to provide a single virtual HLR for a number of corporate wireless networks. Generally, the method includes steps of: (i) coupling the physical HLRs of the corporate wireless networks to one another via an IP network; (ii) coupling an HLR management routing function to the routing function; and (iii) configuring the HLR management routing function to route access requests from the OMC to the physical HLRs, and configuring the OMC to manage each ofthe physical HLRs to provide a single virtual HLR.
In one embodiment, the sites are separate branches of a single private enterprise and the OMC is an OMC of the enterprise, and the step of configuring the OMC to provide a single virtual HLR involves configuring the OMC to provide a single virtual HLR for the separate branches of the enterprise. Preferably, the method further involves adding an OMC of another private enterprise, and configuring the OMCs to manage each of the physical HLRs at their associated separate sites and a shared site to form virtual HLRs for both enterprises.
Advantages of the apparatus and method of the present invention include any or all of the following:
(i) increased system robustness and reliability through the use of multiple independent HLRS;
(ii) consolidation of control and management functions for the HLRs;
(iii) consolidation of subscription management functions, i.e., adding, deleting or altering the profile of subscribers, for the HLRs;
(iv) consolidation of operation and management of alarm functions for the HLRs;
(v) improved utilization of system resources through the reduction or elimination of backhauling of messages from an originating MSC to a remote HLR;
(vi) where an SS7 routing function is included, a single SS7 node address for all of the multiple HLRS; and
(vii) less messaging or signaling between the HLRs and the SS7 network thereby improving efficiency.